This invention relates generally to the field of equipment for handling finger cots or other thin-walled, elastic, tubular members having a single closed end, such as condoms or balloons, and more particularly relates to such equipment which is used to handle, orient, test or otherwise process individual cots. Even more particularly, the invention relates to such equipment which incorporates a set of multiple fingers or rods adapted to receive an individual cot for subsequent expansion and placement onto a mandrel for testing, printing or the like, and to such equipment which utilizes suction to bring the cots to the receiving fingers.
Tubular members such as finger cots, condoms, balloons and the like are formed of an elastic polymeric material and typically are relatively thin with a generally elongated body shape, such that the longitudinal axis length is greater than the cross-sectional diameter, where one end of the body is closed and the other end is open. Such members are difficult to handle in bulk because of the elasticity and friction characteristics inherent in the material of construction, the lack of structural rigidity, the relatively small size, the ease of rupture if mishandled, and other factors. It is desirable in many circumstances, and sometimes required, that individual members be handled, processed or treated in some manner. For example, finger cots and condoms must be tested for holes and imperfections by stretching each condom onto a testing mandrel. Balloons may need to be individually imprinted with designs or lettering.
Apparatuses have been developed for handling finger cots and the like, and one type of such apparatus uses suction to transport and orient individual tubular members through conduits, where the tubular members are retrieved in random orientation from a hopper but delivered in a uniform predetermined orientation. Where the tubular members must be placed onto mandrels for testing or further processing, some of this type of handling equipment utilize a set of slender, elongated fingers or rod elements which are initially disposed in a generally parallel and abutting fashion to pass upwardly into the open end of the tubular element, such that the closed end of the tubular member rests on the tops of the finger elements with the body of the tubular member hanging down and encircling the finger elements. The mandrel is brought into the center of the finger elements, or the finger elements are brought down over the mandrel, such that the mandrel radially expands the finger elements and the tubular member and relative axial movement of the mandrel and finger elements causes the tubular member to be deposited onto the mandrel with the finger elements withdrawn. The finger elements act as runners to reduce friction between the mandrel and the tubular member during the loading process so that the entire tubular member will be disposed onto the mandrel in a fully extended manner. Such apparatuses having finger elements to receive the tubular members are shown for example in U.S. Pat. Nos. 5,499,898 and 5,564,552 to Vonier et al., the disclosures of which are incorporated herein by reference. These patents disclose a condom handling apparatus where the individual condoms are dropped onto the finger elements, with the carriage or mount holding the finger elements being passed over the mandrel axially in order to place the condom onto the mandrel.
In order to maximize the efficiency of the finger elements in receiving and expanding the tubular member, it is known to provide individual finger elements with differing physical structures or configurations. For example, in a set of finger elements mounted onto a carriage, one or more finger elements may be of different lengths, or one or more finger elements may be non-linear, having angled segments or curved segments. Because the tubular elements being disposed onto the finger elements have relatively small inner diameters, and because the tubular elements are composed of highly flexible material which may not retain a circular cross-sectional configuration during handling, it is imperative that the cross-sectional area occupied by the bundle of finger elements be minimized when in the abutted condition for receiving the tubular member, so that all of the finger elements will be disposed within the tubular member when it is placed onto finger elements. This is especially true when handling finger cots, which may have an inner diameter of only about five eighths of an inch. After hundreds and thousands of repetitions where the finger elements are radially expanded and then contracted, the finger elements may become misaligned, causing an increasing numbers of misfeeds, which may eventually require repair or replacement of the finger elements. Furthermore, finger cots are relatively short as well, being typically about two and three quarter inches in length. This causes problems with equipment utilizing the gravity or xe2x80x9cparachutexe2x80x9d method of depositing the tubular member onto the finger elements, where the tubular member is oriented with the open end downward and then dropped onto the finger elements, with air pressure alone acting to expand the tubular member as it falls, in that the margin of error is reduced for the smaller tubular members and any misalignment or reduced pressure expansion during the drop may result in a misfeed.
It is an object of this invention to provide improved tubular member handling apparatuses, and in particular improved finger cot handling apparatuses, where the problems of maintaining concise bundling and alignment of the finger elements and of inadequacies associated with the gravity drop method of disposition of the tubular member onto the finger elements are obviated. It is an object to address these problems in apparatuses employing sets of finger elements to receive the individual tubular members by providing a finger element alignment mechanism which properly aligns and orients the individual finger elements in the bundled or contracted configuration. It is a further object to provide a more controlled method for disposing the tubular members onto the finger elements relative to the gravity drop method, by providing a vacuum mechanism such that the closed end of the tubular member is delivered first to the tips of the finger elements and where the vacuum subsequently inverts the tubular member and draws the open end and body of the tubular member onto the finger elements. It is a further object to provide an apparatus where the finger element alignment mechanism also acts as a sealing gate to provide a closed chamber about the finger elements such that a pressure differential may be created within the closed chamber to pull the tubular member onto the finger elements, the finger element alignment mechanism opening to allow removal of the finger elements and tubular member from the chamber after the tubular member is properly disposed onto the tubular members. These and other intended objects not expressly stated above will be made apparent by the disclosure to follow.
The invention is in general an apparatus and method for disposing thin-walled, elastic, tubular members having one closed end and one open end, such as a finger cot, condom, balloon or the like, onto a set of plural, radially expandable, finger or rod elements mounted onto a carriage assembly, with the finger elements extended upward within the tubular element such that the closed end of the tubular element rests on the tips of the finger elements. The invention comprises in general a vacuum chamber adjoined to tubular member delivery means, where an individual tubular member is drawn into the vacuum chamber closed end first by vacuum means. The finger elements extend into the vacuum chamber through an extraction port and are positioned such that the closed end of the tubular member strikes the tips of the finger elements when it is drawn into the chamber. The vacuum causes the tubular member to invert, such that the body and open end of the tubular member are pulled onto the main bodies of the finger elements.
A finger element alignment means is provided, the alignment means temporarily constraining, orienting and aligning the finger elements such that they are tightly bundled into a small cross-sectional area prior to receipt of the tubular member. The alignment means further acts to temporarily seal the extraction port so that a suction can be created by the vacuum means to draw the tubular member into the vacuum chamber. The alignment means preferably comprises a pair of laterally movable blocks, each having a semi-circular finger element control bore, such that advancing the blocks toward each other produces a fully circular control bore of small diameter to properly align the finger elements, while the blocks themselves combine to seal the extraction port in the vacuum chamber so that suction may be drawn within the vacuum chamber.
The operation sequence for one embodiment comprises advancing the finger elements through the extraction port and into the vacuum chamber, advancing together the finger element alignment means to align the finger elements and seal the extraction port, opening a vacuum gate such that the vacuum means creates negative pressure within the vacuum chamber, thereby drawing a tubular element into the vacuum chamber from tubular element delivery means, with the negative pressure causing the tubular member to invert over and onto finger elements, closing the vacuum gate and retracting the alignment means to open the extraction port, and withdrawing the finger elements and tubular member, with the cycle repeating. In an alternative embodiment, the operation sequence differs in that the finger alignment means are advanced together prior to advancing the finger elements through the extraction port, such that the combination of the finger element alignment means produces a guide bore to direct the finger elements as they are advanced through the extraction port and into the vacuum chamber.